I think the correct answer is option 3. CaCl2 is the compound that is an electrolyte when dissolved in water. An electrolyte is a substance that conducts electricity in solution. Calcium Chloride when in solution dissociates into ions which allows the flow of current in the solution.
https://sciencing.com/make-3d-model-atom-5887341.html
D.) There are 24 atoms in total in that compound.....
Yes, Benzylamine is miscible, meaning it is soluble at all amounts.